<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>1-伪元素和伪类</title>
    <style>
        html {
            font-size: 12px;
        }

        .box1 {
            font-size: 2rem;
            color: tomato;
        }

        .box2 {
            color: pink;
            font-size: 3em;
        }

        .box3 {
            font-size: 24px;
            color: #409FEE;
        }
    </style>
</head>

<body>
    <p class="box1">12345645654</p>
    <p class="box2">12345645654</p>
    <p class="box3">12345645654</p>
</body>

</html>